681632409 has 16 divisors (see below), whose sum is σ = 913508480. Its totient is φ = 452096640.

The previous prime is 681632401. The next prime is 681632477. The reversal of 681632409 is 904236186.

It is not a de Polignac number, because 681632409 - 2³ = 681632401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681632401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 741252 + ... + 742170.

It is an arithmetic number, because the mean of its divisors is an integer number (57094280).

Almost surely, 2^681632409 is an apocalyptic number.

It is an amenable number.

681632409 is a deficient number, since it is larger than the sum of its proper divisors (231876071).

681632409 is a wasteful number, since it uses less digits than its factorization.

681632409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 681632409 is about 26108.0908723713. The cubic root of 681632409 is about 880.0690411569.

The spelling of 681632409 in words is "six hundred eighty-one million, six hundred thirty-two thousand, four hundred nine".